Enantioselective Synthesis of 4‐Isoxazolines by 1,3‐Dipolar Cycloadditions of Nitrones to Alkynals Catalyzed by Fluorodiphenylmethylpyrrolidines

The first organocatalytic enantioselective 1,3‐dipolar reaction between nitrones and alkynals catalyzed by (S)‐2‐(fluorodiphenylmethyl)pyrrolidine to give 4‐isoxazolines (2,3‐dihydroisoxazoles) with high enantiomeric excess, excellent yields and low catalyst loading (1–5 mol%) is presented. The catalytic loading could be reduced to 1 mol% with only slight increases in reaction times.